Minimally invasive biomaterial injection system

ABSTRACT

This invention relates generally to an instrumentation and implant system providing minimally invasive vertebral augmentation. The apparatus including an expandable membrane sized and configured to be located within a cavity in a patient&#39;s bone and having an interior volume for receiving bone filler material; a delivery cannula in communication with the membrane for providing bone filler material to the membrane; and an evacuation cannula in fluid communication with the membrane for receiving a portion of the provided bone filler material from the membrane.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/025,448 (issued as U.S. Pat. No. 9,539,041), filed Sep. 12, 2013,entitled “Minimally Invasive Biomaterial Injection System,” thedisclosure of which is hereby incorporated by reference.

TECHNICAL FIELD

This invention relates generally to an instrumentation and implantsystem for augmenting or supporting bones or other structures including,for example, a vertebral body or intervertebral disc space. Morespecifically, this invention relates to a porous or permeablecontainment device and associated methods and instrumentation for thetreatment of compressed bone voids, more specifically, vertebralcompression fractures and intervertebral disc space.

BACKGROUND

There are various pathologies which results in creation a bone the voidincluding vertebral compression fractures, tumors in bony sections(e.g., vertebral bodies), and treatment of disc degeneration where thedegenerated disc is removed and replaced with an implant. To fill thegap which is created during surgery/degeneration, insertion of abiomaterial is required for providing a bone growth environment(conductive/inductive) as well as for enhancing the mechanical stabilityof the bone.

Vertebral compression fractures (“VCF”) represent a common spinal injuryand may result in prolonged disability. Generally speaking, VCF involvescollapse of one or more vertebral bodies in the spine. VCF usuallyoccurs in the lower vertebrae of the thoracic spine or the uppervertebrae of the lumbar spine and generally involves fracture of theanterior portion of the affected vertebral body. Such spinal compressionfractures and related spinal deformities, if not successfully treated,can lead to deformation of the normal alignment or curvature, e.g.,lordosis, of the affected area of the spine, as well as chroniccomplications and an overall adverse impact upon the quality of life forthe patient. Until recently, doctors were limited to treating suchcompression fractures and related deformities with pain medications, bedrest, bracing or invasive spinal surgery.

More recently, minimally invasive surgical procedures for treatingvertebral compression fractures, tumors in the bony sections (e.g.,vertebral bodies), and disc degeneration have been developed. Theseprocedures generally involve the insertion of a rigid cannula, needle ortrocar into the interior of a collapsed or otherwise damaged vertebra.The cannula usually includes a lumen or central passage through whichanother tool, implant or filler material is passed in order toreposition and/or augment the vertebral body.

Delivering originally solid state biomaterial (e.g., autograft bone)through a minimally invasive access (cannula) to fill the created voidhas proven to be challenging procedure due to the geometricalconstraints of the access cannula as well as friction between boneparticles within the cannula during insertion. The most basic of theseprocedures is vertebroplasty. Vertebroplasty involves injecting amedical-grade bone cement (such as polymethylmethacrylate, a.k.a., PMMA)via a special bone needle into a fractured vertebra. The bone cement isinjected with sufficient pressure to compress and displace cancellousbone tissue. However, the direction and containment of the injectedcement can be difficult to control because the space the bone cementoccupies is ill-defined, self-forming, and highly-dependent upon theinternal composition of the cancellous bone. Additionally,vertebroplasty does not always reposition the fractured bone andtherefore may not address the problem of spinal deformity due tofracture.

A number of more advanced treatments for vertebral compressionfractures, tumors in the bony sections, and disc degeneration are known,and generally involve two phases: (1) reposition, or restoration of theoriginal height/shape of the vertebral body/bone void (and consequentlordotic correction of the spinal curvature); and (2) augmentation, oraddition of material to support or strengthen the fractured bone. Suchprocedures generally involve use of a cannula, catheter, needle, trocaror other introducer to provide access to the interior of the effectedvertebral body.

Procedures, such as kyphoplasty, provide better bounding and controlover injected bone cement, other procedures utilize devices for firstforming cavities within the cancellous bone (and, accordingly, otherinterior body regions) prior to injecting bone cement into such acavity. During balloon kyphoplasty (Kyphon, Inc.), an expandable body orballoon is deployed into the interior body region to form a cavity in,for example, cancellous bone tissue surrounded by fractured corticalbone. Kyphoplasty then achieves the reconstruction of the lordosis, ornormal curvature, by inflating the balloon, which expands within thevertebral body restoring it to its original height. These expandablebody devices effectively compress and displace the cancellous bone toform an interior cavity that then receives a filling material intendedto provide renewed interior structural support for cortical bone.

A common drawback of most systems for repositioning and augmentingdamaged vertebrae/bone voids is that they involve the use of multiplecomplex instruments introduced through rigid introducers. Theseintroducers limit the surgeon's ability to access portions of thepatient's spine. Similarly, these systems do not allow the surgeon tocontrol the location and composition of the bone cerement provided tothe bone cavity. Furthermore, delivering bone graft and solid statematerial into the intervertebral disc space through a minimally invasiveaccess is challenging as the solid state material tends to jam on theway to the intended point. Accordingly, there remains a need in the artto provide a safe and effective apparatus and methods for minimallyinvasive repositioning of and osteopathic augmentation of vertebralbodies to restore lordosis of the spine.

SUMMARY

Presented are systems and methods for minimally invasive vertebralaugmentation and restoration of spinal lordosis. An aspect of thepresent invention is directed to an apparatus including a porous orpermeable membrane is provided into an interior volume/void in atargeted vertebral body. The membrane configured to receive bone fillermaterial thereby restoring the anatomy of the targeted vertebral body.The apparatus including an expandable membrane sized and configured tobe located within the cavity in the patient's bone, the expandablemembrane having an interior cavity for receiving the bone fillermaterial. The device further includes a delivery cannula in fluidcommunication with the membrane for providing bone filler material tothe expandable membrane. The device also includes an evacuation cannulain fluid communication with the membrane for receiving a portion of theprovided bone filler material from the membrane.

Another aspect of the present disclosure is directed to a method ofaugmenting void in a patient's bone, e.g., a void in a vertebral body.The method may include placing an expandable membrane into an interiorvoid in a vertebral body and providing bone filler material to through adelivery cannula to the membrane. The membrane may be expanded byinjection of an amount of bone filler material and a portion of the bonefiller material may be removed from the membrane via an evacuationcannula.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the invention will be apparent from thedescription and drawings, and from the claims.

DESCRIPTION OF DRAWINGS

The device is explained in even greater detail in the followingdrawings. The drawings are merely examples to illustrate the structureof preferred devices and certain features that may be used singularly orin combination with other features. The invention should not be limitedto the examples shown.

FIG. 1 is a plan view of an example apparatus;

FIG. 2A is a partial cross-section view of an example apparatus;

FIG. 2B is a partial cross-section view of an example membrane;

FIG. 3 is a partial cross-section view of an example apparatus;

FIG. 4 is a plan view of another example apparatus;

FIG. 5 is a partial cross-section of an example delivery cannula;

FIG. 6A is a partial side view of an example apparatus;

FIG. 6B is a partial side view of an example apparatus;

FIG. 6C is a partial side view of an example apparatus;

FIG. 7 is a partial view of an example intervertebral disc space duringinsertion and expansion of the membrane;

FIG. 8 is a partial cross-section view of an example apparatus; and

FIG. 9 is a partial cross-section view of an example apparatus withinthe intervertebral disc space.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

Certain terminology is used in the following description for convenienceonly and is not limiting. The words “right”, “left”, “lower”, and“upper” designate direction in the drawings to which reference is made.The words “inner”, “outer” refer to directions toward and away from,respectively, the geometric center of the described feature or device.The words “distal” and “proximal” refer to directions taken in contextof the item described and, with regard to the instruments hereindescribed, are typically based on the perspective of the surgeon usingsuch instruments. The terminology includes the above-listed words,derivatives thereof, and words of similar import.

In addition, various components may be described herein as extendinghorizontally along a longitudinal direction “L” and lateral direction“A”, and vertically along a transverse direction “T”. Unless otherwisespecified herein, the terms “lateral”, “longitudinal”, and “transverse”are used to describe the orthogonal directional components of variousitems. It should be appreciated that while the longitudinal and lateraldirections are illustrated as extending along a horizontal plane, andthat the transverse direction is illustrated as extending along avertical plane, the planes that encompass the various directions maydiffer during use. Accordingly, the directional terms “vertical” and“horizontal” are used to describe the components merely for the purposesof clarity and illustration and are not meant to be limiting.

Certain examples of the invention will now be described with referenceto the drawings. In general, such embodiments relate to a porous orpermeable membrane inserted into an interior volume/void in a targetedvertebral body and providing bone filler material to the device torestore the anatomy of the targeted vertebral body.

FIG. 1 provides a perspective view of an example apparatus 100. Theapparatus 100 can include a membrane 110, delivery cannula 120 andevacuation cannula 130. The membrane 110 may be sized and configured forinsertion into and location in a cavity/void/volume within a patient'sbone (e.g., a targeted vertebral body V) or a void between bony parts(e.g., a targeted intervertebral disc space V). As will be provided inmore detail below, the membrane 110 may be composed of a flexible,semi-flexible, or rigid material. The membrane 110 can be composed of abiocompatible material. For example the membrane 110 may be composed ofa shape memory alloy (nitinol), titanium, stainless steel, metal alloy,resorbable material (e.g., resorbable polymer), non-resorbable material(e.g., non-resorbable polymer), ceramic, combination thereof. Themembrane 110 can include an interior cavity for receiving bone fillermaterial 140. The bone filler material 140 can include both solidmaterial particles 142 and a carrier fluid 144 (e.g., saline). In anexample apparatus 100, large solid material particles 142 can be brokeninto a granulate form and mixed with the carrier fluid 144 to create agranulate/fluid emulsion. The solid material 142 can include, forexample, bone chips, autograft, allograft, or xenograft bone or anyother filling material now or hereafter known in the art. Preferably thebone filler material 140 is a biocompatible bone cement capable ofintegrating with the surrounding bone tissue found in the bone cavity ofthe targeted intervertebral disc space V or vertebral body V. The bonefiller material 140 may also include a radio-opaque material. Likewise,the bone filler material 140 can include a radiolucent material toenhance visibility of the bone filler material 140 and membrane 110during radiographic imaging. It is contemplated that the filler material140 can be tracked/imaged during the medical procedure placing themembrane 110 and filler material 140 into the void, i.e., intraoperativetracking. Likewise, it is contemplated that the injected and/or hardenedfiller material 140 can be imaged post-procedure.

Filling of the cavity formed in the vertebral body V (or intervertebraldisc space V) and the stabilization of the targeted vertebral body V isaccomplished by the injection of the bone filler material 140, theexpansion of the membrane 110, and removal of all or a portion of thecarrier fluid 144 such that the solid material 142 accumulates in themembrane 110, as will be described in greater detail below. The membrane110 can remain in the void or can be removed to leave only the bonefiller material 140. It is also contemplated that the expansion of themembrane 110 will include the controlled secretion of the bone fillermaterial 140 out of or through the pores provided in the membrane 110.

The membrane 110 can be composed of a flexible material such that themembrane 110 expands when filled with the bone filler material 140. Forexample, the membrane 110 can be expanded from a first, non-expanded,configuration to a second, expanded, configuration via injection of thebone filler material 140 into the membrane 110. In the first,non-expanded, configuration, the membrane 110 can be sized andconfigured for insertion into interior cavity through a minimallyinvasive apparatus, e.g., a cannula. The membrane 110 can be flexiblesuch that the shape of the second, expanded, configuration of themembrane 110 can be defined by the shape/volume of the bone cavity. Inanother example, the membrane 110 can be semi-constrained or selectivelyreinforced such that the second, expanded, configuration of the membrane110 can be predefined. For example, the expanded configuration of themembrane 110 can define a sphere, a cylinder, a cone, a square, arectangle, a torus, a dog bone, a regular shape, an irregular shape, orany other desired shape. In a further example, the expandedconfiguration of the membrane 110 can include a partially defined shape.That is, the expanded membrane 110 can define a predetermined shape andalso be flexible and/or deformable based on the shape/volume defined bythe bone cavity. In another example, the membrane 110 can be constructedfrom a shape memory material such that the membrane 110 has a first,flexible, configuration prior to insertion and a second, previouslydefined, shape after insertion.

FIG. 2A provides a partial cross-section view of an example apparatus100 illustrating the delivery cannula 120 and a permeable membrane 110.FIG. 2B provides a partial cross-section view of an example membrane110. As illustrated in FIG. 2B, the membrane 110 can include a bodyportion 112 constructed from a porous material. For example, the bodyportion 112 of the membrane 110 can include a plurality ofpores/openings 114 allowing a portion of the bone filler material 140(e.g., solid material 142 and/or carrier fluid 144) injected into themembrane 110 to flow out of or through the membrane 110 into the bonecavity. It is contemplated that the pores/openings 114 can be uniform insize and shape and be uniformly distributed on the body portion 112 ofthe membrane 110. That is, the pores/openings 114 can be located on thebody portion 112 such that the outflow of filler material 140 isuniformly directed within the bone cavity. In another example, theopenings 114 can be distinct in size, shape, and/or distribution on thebody portion 112 of the membrane 110 such that outflow of the fillermaterial 140 is directed to a desired location at a desiredvolume/velocity within the bone cavity. The pores/openings 114 candefine a round, square, rectangular, oval, or any other regular orirregular shape. It is contemplated that the size, location, and numberof the pores/openings 114 can be adjusted to provide for acontrolled/directed secretion of filler material 140 from the membrane110. For example, FIG. 3 provides a partial cross-section view of anexample apparatus 100 including a membrane 110 having a porous section(pores/openings 114) located at the distal end 116 of the body portion112. Accordingly, bone filler material 140 is provided via the deliverycannula 120 into the membrane 110 in the direction of arrow A. Thecarrier fluid 144 and solid material 142 (of a particular size) of thefiller material 140 are excreted from the distal end 116 of the membrane110 and into the bone cavity in the direction of arrows B. The bonefiller material 140 secreted from the membrane 110 can form a fillermaterial/cement layer around the membrane 110 to facilitate integrationof the membrane 110 with the surrounding bone tissue. Accordingly,filing of the bone cavity and stabilization of the targeted vertebralbody V is accomplished by the injection of the bone filler material 140,the expansion of the membrane 110, and the controlled secretion of thebone filler material 140 out of or through pores/openings 114.

As illustrated in FIG. 1, the apparatus 100 includes delivery cannula120 and evacuation cannula 130. The delivery cannula 120 and theevacuation cannula 130 can be constructed from a flexible,semi-flexible, or rigid material. For example, the delivery cannula 120and the evacuation cannula 130 can be constructed from a flexiblebiocompatible material such as a flexible polymer. In other examples,the delivery cannula 120 and/or evacuation cannula 130 can beconstructed from medical grade silicone, PCU (poly carbonate urethane),PE (polyethylene), or a super-elastic shape memory alloy, etc. Inanother example, the delivery cannula 120 and/or evacuation cannula 130can be constructed from a flexible or rigid material that is woven,knitted, braided, or otherwise interlaced to form a flexible cannula.Because the delivery and evacuation cannulae 120, 130 can be flexible,the delivery and evacuation cannulae 120, 130 provide access to areas inthe patient's spine inaccessible by rigid systems and can limit damageto body structures (muscle tissue, nerve structures, etc.) caused bydelivery and use of more rigid cannulae. A flexible delivery cannula 120and/or evacuation cannula 130 can be inserted into the target locationin the patient's body using a steerable delivery cannula such thatdamage to internal body structures is avoided/limited. In an otherexample, a flexible delivery cannula 120 and/or evacuation cannula 130can include a steerable structure such that the delivery cannula 120and/or evacuation cannula 130 is itself guidable to the desired locationwithin the patient. The location of the delivery cannula 120 and/orevacuation cannula 130 can be monitored and tracked using variousnavigation and/or neuromonitoring tools known in the art.

The delivery cannula 120 is in communication with the membrane 110 andis sized and configured to provide bone filler material 140 (carrierfluid 144 and/or solid material 142) to the expandable membrane 110. Thedelivery cannula 120 can be sized to deliver both the solid material 142and the carrier fluid 144 of the bone filler material 140 to themembrane 110. The evacuation cannula 130 is also in fluid communicationwith the membrane 110 and is sized and configured to receive a portionof the bone filler material 140 provided to the membrane 110 by thedelivery cannula 120. The evacuation cannula 130 can be sized to receivethe carrier fluid 144 and/or solid material 142 particles of apredetermined size. The evacuation cannula 130 can be used to removebone filler material 140 (carrier fluid 144 and/or solid material 142)from the membrane 110 during and/or after expansion of the membrane 110within the bone cavity. For example, bone filler material 140 may beremoved during expansion in an effort to maintain a desired pressureand/or desired expansion of the membrane 110. Bone filler material 140may also be removed from the membrane 110 after expansion. For example,all or a portion of the carrier fluid 144 may be removed from themembrane 110 such that the solid material 142 of the bone fillermaterial 140 accumulates in the membrane 110. In an other example,carrier fluid 144 along with solid material 142 of a particular size maybe removed via the evacuation cannula 130 such that solid material 142of an other size remains in the membrane 110.

It is contemplated that the delivery cannula 120 and the evacuationcannula 130 are releasably coupled to the membrane 110 such that oncethe desired amount of bone filler material 140 has been delivered to themembrane 110 and the expanded membrane 110 is at its desiredconfiguration, the delivery cannula 120 and the evacuation cannula 130can be removed/released from the membrane 110 and the membrane 110 canremain as an implant in the cavity.

To facilitate delivery bone filler material 140 to the membrane 110, theapparatus 100 can include an input member 150. As illustrated in FIG. 1,the proximal end 122 of the delivery cannula 120 can be coupled to andin fluid communication with the input member 150. The input member 150can direct bone filler material 140 into the delivery cannula 120 andthereby into the membrane 110. The input member 150 can direct bonefiller material 140 at a predetermined rate and pressure. An exampleinput member 150 includes a syringe. The input member 150 can include astorage element 152 for storing a quantity of bone filler material 140for insertion into the membrane 110. The input member 150 can be used toadjust the proportion/ratio of the solid material 142 to the carrierfluid 144 in the bone filler material 140 delivered to the membrane 110.

To facilitate removal of bone filler material 140 from the membrane 110,the apparatus 100 can include an output member 160. As illustrated inFIG. 1, the proximal end 132 of the evacuation cannula 130 can becoupled to and in fluid communication with the output member 160. Theoutput member 160 can direct bone filler material 140 through theevacuation cannula 130 and away from the membrane 110. The output member160 can include a storage element 162 for storing a quantity of bonefiller material 140 received from the membrane 110. In an exampleapparatus 110, the output member 160 can be operably coupled to asuction device for drawing the portion of the bone filler material 140through the evacuation cannula 130 and away from the membrane 110. Theoutput member 160 can direct bone filler material 140 from the membrane110 at the same rate and/or pressure as the input member 150 deliversbone filler material 140. In another example, the output member 160 candirect bone filler material 140 from the membrane 110 at a differentand/or varying rate and/or pressure than the input member 150 deliversthe material to the membrane 110. In an example apparatus 100, the rateand/or pressure (suction) of the output device 160 is determined by thesuction device the output device 160 is coupled to. In a further exampleapparatus 100, the particle size and rate of removal from the membrane110 can be defined based on the size/area of the coupling between themembrane 110 and the evacuation cannula 130. For example, the evacuationcannula 130 having a circular cross-section can have a radialcross-section defining an area (e.g., A=πr² _(evacuation)) less than thearea of the radial cross section of the delivery cannula 120 having acircular cross-section (e.g., A=πr² _(delivery)). As such, theevacuation cannula 130 may withdraw filler material 140 from themembrane 110 at a rate and volume less than that of the delivery cannula120. Similarly, the area defining the coupling between the evacuationcannula 130 and the membrane 110 can define the size of particles thatmay be transmitted into the evacuation cannula 130. For example, thearea defined by the coupling may be such that the evacuation cannula 130may only receive carrier fluid 144 and solid material 142 of aparticular size. In another example, a filter 135 can be coupled to theevacuation cannula 130 at a location between the evacuation cannula 130and the membrane 110 such that the filter 135 prevents bone fillermaterial 140 of a predetermined size from passing into the evacuationcannula 130. In an example apparatus 100, the composition of the removedbone filler material 140 can comprise at least 50% carrier fluid 144. Ina further example, the composition of the removed bone filler material140 can comprise greater than 50% carrier fluid 144.

As illustrated in the example apparatus 100 of FIG. 1, the deliverycannula 120 and the evacuation cannula 130 can be coupled to themembrane 110 at different locations. For example, the delivery cannula120 can be located adjacent to the evacuation cannula 130. In an otherexample (not shown), the evacuation cannula 130 can be located at alocation distant or opposite on the membrane 110 from the deliverycannula 120. For example, the delivery cannula 120 can be located on theproximal end 118 of the membrane 110 and the evacuation cannula 130 canbe located at the distal end 116 of the membrane 110. It is contemplatedthat the evacuation cannula 130 and the delivery cannula 120 can belocated at any position on the membrane 110.

In another example apparatus 100 illustrated in FIG. 4, the deliverycannula 120 extends within the evacuation cannula 130. FIG. 4 provides aplan view of the example apparatus 100 having the combineddelivery/evacuation cannula design. FIG. 5 provides a partialcross-section view of the example delivery cannula 120 and evacuationcannula 130. As illustrated, the delivery cannula 120 extends throughthe evacuation cannula 130 providing filling material 140 to themembrane 110 in the direction of arrows A. As outlined above, theevacuation cannula 130 can be used to remove carrier fluid 144 and solidmaterial 142 of a particular size from the membrane 110. As illustratedin FIGS. 4 and 5, the evacuation cannula 130 can terminate proximate themembrane 110. For example, the evacuation cannula 130 can remove carrierfluid 144 (and/or solid material 142) that passes through the openings114 provided in the membrane 110. In another example (not shown), theevacuation cannula 130 can be coupled to the membrane 110 such thatcarrier fluid 144 (and/or solid material 142) can be removed directlyfrom the main cavity of the membrane 110. The evacuation cannula 130removes the carrier fluid 144 and the particular size solid material 142in the direction of arrows B. The particle size and rate of removal fromthe membrane 110 can be defined based on the size/area of the couplingbetween the membrane 110 and the evacuation cannula 130. Accordingly,the coupling area of the evacuation cannula 130 and the membrane 110 iscalculated based on the area defined by difference between theevacuation cannula 130 and the delivery cannula 120 (e.g., assuming theevacuation cannula 130 and delivery cannula 120 have circularcross-sections, the evacuation cannula 130 coupling areaArea=π(r_(evacation))²−π(r_(delivery))²). As such, the evacuationcannula 130 can be configured to receive carrier fluid 144 and solidmaterial 142 of a particular size. As illustrated in FIG. 5, element “d”identifies the difference between the radius of the delivery cannula 120and the radius of the evacuation cannula 130. Accordingly, thisdifference (d) identifies the largest particle size of the solidmaterial 142 capable of being withdrawn via the evacuation cannula 130.It is also contemplated that the difference (d) between the deliverycannula 120 and the evacuation cannula 130 can be such that only thecarrier fluid is removed from the membrane 110. For example, thedifference (d) can be such smaller than the particle size of the solidmaterial 142 included in the filler material 140.

In a further example, the membrane 110 can be constructed from aflexible material and include a withdraw element 170 capable ofwithdrawing the flexible membrane 110 off the filler material 140. FIGS.6A and 6B provide side views of an example membrane 110 constructed froma flexible material and including a withdraw element 170 for removingthe membrane 110 material from the filler material 140. The withdrawelement 170 can be coupled to the membrane 110 to permit the membrane110 to release from the filler material 140 upon movement of thewithdraw element 170 towards the proximal end 118 of the membrane 110.An example withdraw element 170 can include a flexible wire/string.Another example withdraw element 170 can include a tube coupled to themembrane 110. As illustrated in FIG. 6A, with withdraw element 170 canbe coupled to the distal end 116 of the membrane 110 at point A andwithdrawn in a direction towards the proximal end 118 of the membrane110 illustrated by arrows B. FIG. 6B illustrates the material of theflexible membrane 110 partially withdrawn off the filler material 140and folded back onto the remaining membrane 110 material, area C. As inthis example, because the membrane 110 does not remain in the patient,it can be considered as part of the apparatus 100 facilitating deliveryand placement of the biomaterial in the cavity.

In another example (now shown), the withdraw element 170 is coupled tothe membrane 110 such that as the withdraw element 170 is moved is adirection towards the proximal end 118, the membrane 100 is removed fromthe filler material 140 without folding back onto itself. For example,the withdraw element 170 can be coupled to the proximal end 118 of themembrane 110 and/or along the length of the membrane 110. Movement ofthe withdraw element 170 causes the membrane 110 to release from thedelivery cannula 120 and move over the filler material 140 and thedelivery cannula 120 in a direction towards the proximal end 118 of theapparatus 100.

In operation, the bone filler material 140 can be provided to themembrane 110 via the delivery cannula 120. The carrier fluid 144 (andpossibly some solid material 142 depending in contact area defined bythe evacuation cannula 130) is removed from the membrane 110. Once thefiller material 140 is sufficiently set/formed within the bone cavity,the withdraw element 170 can be used to drawn the flexible material ofthe membrane 110 off the set filler material leaving only the fillermaterial within bone cavity.

FIG. 6C provides a perspective cross-section view of another examplemembrane 110. The membrane 110 can be constructed from a flexiblematerial and include an outer layer 110 a and an inner layer 110 b. Theouter layer 110 a can be coupled to the evacuation cannula 130/outercannula of the apparatus 100. The inner layer 110 b can be coupled tothe delivery cannula 120/inner cannula of the apparatus 110. Either oneof the outer layer 110 a or the inner layer 110 b can alternatively bepermeable. For example, as illustrated in FIG. 6C, the inner layer 110 bcan include openings 114 and the outer layer 110 a can be solid. It isalso contemplated that both the outer layer 110 a and the inner layer110 b can be permeable, including openings 114 (of similar or varyingsize) to provide for the flow of carrier fluid 144 and/or solid material142, or impermeable. The membrane 110 can include a ring 154 located atthe distal end 116 of the membrane 110. The ring 154 can provide acoupling point for the outer layer 110 a and inner layer 110 b. The ring154 can include an opening between the inner volume of the membrane 110and the void within the patient. The opening in the ring 154 can besized to permit the flow of carrier fluid 144 and/or solid material 142of a particular size from the inner volume of the membrane to the void.In another example (not shown), the ring can no include an opening.

In operation, bone filler material 140 is provided to the membrane 110via the delivery cannula 120 in the direction of arrow A. Solid material142 will collect within the interior volume defined by the inner layer110 b. The carrier fluid 144 (and possibly some solid material 142depending on the area defined by the openings in the inner and/or outerlayers 110 b, 110 a and/or the opening in the ring 154) is removed fromthe membrane 110. For example, where the inner layer 110 b and/or outerlayer 110 a are permeable, the carrier fluid 144 and/or solid material142 (of a particular size) can pass from the inner volume of themembrane 110 to the evacuation cannula 130, in the direction of arrowsB. It is also contemplated that carrier fluid 144 and/or solid material142 (of a particular size) can pass through the opening in the ring 154and into the void in the direction of arrow C. Where the outer layer 110a is permeable, carrier fluid 144 and/or solid material 142 that haspassed through the opening in the ring 154 can also pass into theevacuation cannula 130 via the openings 114 in the outer layer 110 a.The carrier fluid 144 and/or solid material 142 is then drawn throughthe evacuation cannula 130 in the direction of arrows D. Once the fillermaterial 140 is sufficiently set/formed within the inner volume of themembrane 110, the membrane 110 can be removed from the set fillermaterial, leaving the filler material 140 within the cavity. Theevacuation cannula 130/outer cannula of the apparatus 100 can facilitateremoval of the membrane 110 from the filler material. For example, asevacuation cannula 130/outer cannula of the apparatus 100 can be movedwith respect to the delivery cannula 120/inner cannula of the apparatus110, the outer layer 110 a is moved with respect to the inner layer 110b. In an example apparatus 100, as the evacuation cannula 130 is movedin the direction of arrows E, away from the membrane 100, the outerlayer 110 a (and membrane 110) is removed from the filler material 140.The ring 154 can be made of a fragile material that such that it willfracture when sufficient force is applied from the outer layer 110a/evacuation cannula 130. Once the ring 154 is fractured, the membrane100 (inner layer 110 b and outer layer 110 a) can be withdrawn off ofthe filler material. Once removed from the filler material 140, theinner layer 110 a can separate from the delivery cannula 120 and theentirety of the membrane 110 removed from the filler material 140,leaving only the filler material 140 within the cavity. In anotherexample, the ring 154 can be constructed from a flexible material suchthat the ring 154 stretches/flexes as the membrane 110 is removed fromthe filler material 140.

In use, the membrane 110, in its first, non-expanded, configuration isinserted preferably via a minimally invasively apparatus (e.g., cannula)into a targeted zone. FIG. 7 provides a partial view of an exampletarget zone including an intervertebral disc space V during insertionand expansion of the membrane 110. Bone filler material 140 is thenprovided to the membrane 110 through the delivery cannula 120 by inputmember 150. The membrane 110 is expanded from an insertion configurationto an expanded configuration via injection of the bone filler material140 into the inner cavity of the membrane 110. Expansion of the membrane110 can compress and/or contact the surrounding cancellous bone tissueof the targeted intervertebral disc space V thereby forming and/orfilling the cavity. The membrane 110 can expand to define apredetermined or predisposed shape. In another example, the shape of theexpanded membrane 110 can be defined by the shape of the bone cavity.Expansion of the membrane 110 can reposition and stabilize thesurrounding bone and/or bone tissue. That is, the membrane 110, in theexpanded configuration, is structurally strong enough to impart a forceto the surrounding bone tissue in the cavity of the targetedintervertebral disc space V sufficient to restore the anatomicalalignment of the intervertebral disc space V until hardening of theinjected bone filler material is complete.

FIG. 8 provides a partial cross-section view of an example membrane 110during injection of the bone filler material 140 in the direction forarrow A. In an example apparatus 100, solid material 142 of constant (orvarying) size is distributed throughout the bone filler material 140 andinjected into the membrane 110. In another example apparatus 100, thebone filler material 140 is injected into the membrane 110 by injectinga first volume of bone filler material 140 having a first solid particlesize 142 a and subsequently injecting a second volume of bone fillermaterial 140 having a second solid particle size 142 b such that thefirst particle size 142 a is greater than the second particle size 142b. That is, the composition of the bone filler material 140 is adjustedsuch that filler material 140 having a large particle size (e.g., firstsolid particle 142 a) is injected first into the membrane 110 and fillermaterial 140 having a smaller particle size (e.g., second solid particle142 b) is injected second into the membrane 110. It is furthercontemplated that filler material 140 with solid particles having asmaller particle size may be injected first into the membrane 110followed by filler material 140 with solid particles having a largerparticle size.

A portion of the bone filler material 140 (e.g., the carrier fluid 144and/or solid material 142 of a particular size) may be removed from themembrane 110 through the evacuation cannula 130 (direction of arrow B inFIG. 8) by the output member 160. The bone filler material 140 may beremoved from the membrane 110 until a desired proportion of solidmaterial 142 to carrying fluid 144 is present in the filler material 140inserted into the membrane 110. It is also contemplated that the fillermaterial 140 may be injected into and removed from the membrane 110until the desired portion of solid material 142 is present in themembrane 110.

The outer surface of the membrane 110 can be porous such that an amountof bone filler material 140 is secreted out of or through the membrane110. In another example, the pores/openings 114 can be located on thebody portion 112 of the membrane 110 such that the bone filler material140 is directionally secreted from the membrane 110. In an exampleapparatus, a relatively small amount of bone filler material 140 may besecreted out of or through the membrane 110 via one or morepores/openings 114 formed in the membrane 110. Once secreted, the bonefiller material 140 can cure to form a cement layer around the membrane110 that integrates with the surrounding bone tissue.

As outlined above, the bone filler material 140 can include aradiolucent material to enhance visibility of the membrane 110 duringradiographic imaging. Accordingly, radiographic (x-ray) imaging may beused during expansion of the membrane 110 to determine the desireddistribution of filler material 140. Likewise, radiographic (x-ray)imaging may be used during injection of filler material 140 to determinethe desired repositioning of the intervertebral disc space V andexpansion of the membrane 110. FIG. 9 provides an example radiographicimage illustrating radiolucent material (elements A) present in thefiller material 140.

Once the bone filler material 140 is inserted into the membrane 110 (andthe desired portion of carrying fluid 144 and/or solid material 142 hasbeen removed), the bone filler material 140 begins to cure within thebone cavity. In an example apparatus, the membrane 110, enclosing thecured bone filler material 140, remains within the bone cavity of thetargeted vertebral body V/intervertebral disc space V and is consideredpart of the implanted material. This implant-type membrane 110 canassist in load bearing and structural support of the vertebral bodyV/intervertebral disc space V as the bone filler material 140 cures. Inanother example, the implant-type membrane 110 is constructed from abioresorbable material that is absorbed, over time, into the body. In afurther example, the membrane 110 is constructed from a flexiblematerial such that, as the bone filler material 140 cures within thecavity, the flexible material of the membrane 110 is removed from thecured (and/or partially cured) bone filler material 140, leaving thebone filler material 140 within the cavity. In such an example, themembrane 100 can be considered part of the apparatus 100 forfacilitating delivery and placement of the bone filler material to thevoid.

As outlined above, the membrane 110, delivery cannula 120, andevacuation cannula 130 may be composed of a biocompatible material knownincluding, for example, metals such as titanium, titanium alloys,stainless steel and cobalt chromium, cobalt chromium molybdenum(CoCrMo), or other metals. Other materials include, for example,composites, polymers, or ceramics. In one example, one or morecomponents of the apparatus 100 can be constructed from a radiopaquematerial including, for example, stainless steel such as 17-4PHstainless steel. Likewise, one or more components described herein canbe constructed from a radiolucent material to enhance visibility of theassembly during radiographic imaging. Example radiolucent materials caninclude “life science” grade PEEK (Ketron 450G PEEK). Life science gradePEEK can improve wear and abrasion characteristics as well as providehigh yield strength. A coating may be added or applied to the variouscomponents described herein to improve physical or chemical properties,such as a plasma-sprayed titanium coating or Hydroxypatite. Moreover,skilled artisans will also appreciate that the various components hereindescribed can be constructed with any dimensions desirable forimplantation and cavity creation.

While the foregoing description and drawings represent the preferredembodiment of the present invention, it will be understood that variousadditions, modifications, combinations and/or substitutions may be madetherein without departing from the spirit and scope of the presentinvention as defined in the accompanying claims. In particular, it willbe clear to those skilled in the art that the present invention may beembodied in other specific forms, structures, arrangements, proportions,and with other elements, materials, and components, without departingfrom the spirit or essential characteristics thereof. One skilled in theart will appreciate that the invention may be used with manymodifications of structure, arrangement, proportions, materials, andcomponents and otherwise, used in the practice of the invention, whichare particularly adapted to specific environments and operativerequirements without departing from the principles of the presentinvention. In addition, features described herein may be used singularlyor in combination with other features. The presently disclosedembodiments are, therefore, to be considered in all respects asillustrative and not restrictive, the scope of the invention beingindicated by the appended claims and not limited to the foregoingdescription.

It will be appreciated by those skilled in the art that changes could bemade to the embodiments described above without departing from the broadinventive concept thereof. It is understood, therefore, that thisinvention is not limited to the particular embodiments disclosed, but itis intended to cover modifications within the spirit and scope of thepresent invention, as defined by the following claims.

What is claimed is:
 1. An apparatus for providing a bone filler materialto a cavity in a patient's bone, the apparatus comprising: an expandablemembrane sized and configured to be located within the cavity in thepatient's bone, the expandable membrane having an interior volume forreceiving the bone filler material; a delivery cannula in fluidcommunication with the membrane for providing bone filler material tothe membrane; an evacuation cannula in fluid communication with themembrane for receiving a portion of the provided bone filler materialfrom the membrane during and after expansion of the membrane within thecavity in the patient's bone, and a filter coupled to the evacuationcannula at a location between the evacuation cannula and the membranesuch that the filter prevents bone filler material of a predeterminedsize from passing into the evacuation cannula.
 2. The apparatus of claim1, wherein the membrane is composed of a flexible material.
 3. Theapparatus of claim 2, wherein at least a portion of the delivery cannulaand the evacuation cannula are constructed from a flexible material. 4.The apparatus of claim 1, wherein the membrane is porous and includes aplurality of openings allowing a portion of the bone filler material toflow out of the membrane and into the cavity in the patient's boneduring expansion of the membrane.
 5. The apparatus of claim 4, whereinthe size, shape, or location of the plurality of openings allows for thecontrolled outflow of a portion of the bone filler materials.
 6. Theapparatus of claim 4, wherein the controlled outflow of the portion ofbone filler material is directed to a desired location at a desiredvolume or velocity within the cavity in the patient's bone.
 7. Theapparatus of claim 1, wherein the membrane is composed of abiocompatible material including at least one of a shape memory alloy(nitinol), titanium, stainless steel, metal alloy, resorbable polymer,non-resorbable polymer, ceramic, combination thereof.
 8. The apparatusof claim 1, wherein in the membrane is expandable from a first,non-expanded, configuration to a second, expanded, configuration viainjection of the bone filler material into the membrane.
 9. Theapparatus of claim 8, wherein the membrane is configured such that thesecond configuration is capable of being defined by a shape of a cavityin a patient's bone.
 10. The apparatus of claim 8, wherein theexpandable membrane is sized and configured to accumulate solid materialof the bone filer material within the interior volume of the expandablemembrane such that the expandable membrane is maintained in the second,expanded, configuration.
 11. The apparatus of claim 8, wherein themembrane includes a reinforcing member for restricting expansion of themembrane such that at least one of a size and a shape of the membrane inthe second configuration is predefined.
 12. The apparatus of claim 9,wherein the second configuration defines a shape including at least oneof a sphere, a cylinder, a square, a rectangle, a cone, a torus, a dogbone, a regular shape, and an irregular shape.
 13. The apparatus ofclaim 1, wherein the delivery cannula extends within at least a portionof the evacuation cannula.
 14. The apparatus of claim 1, wherein theevacuation cannula is coupled to the membrane at a location other than acoupling location of the delivery cannula.
 15. The apparatus of claim 1,further including an input member in fluid communication with thedelivery cannula, the input member directing bone filler material intothe delivery cannula.
 16. The apparatus of claim 1, wherein the bonefiller material includes a solid material and a carrying fluid, and theinput member can adjust a ratio of the solid material to the carryingfluid in the bone filler material, wherein the solid material comprisesat least one of a biocompatible bone cement, bone chips, autograft,allograft, and xenograft bone.
 17. The apparatus of claim 1, furtherincluding an output member in fluid communication with the evacuationcannula, the output member directing a portion of the bone fillermaterial through the evacuation cannula away from the membrane.
 18. Theapparatus of claim 17, wherein the output member is operably coupled toa suction device for drawing the portion of the bone filler materialthrough the evacuation cannula away from the membrane.
 19. The apparatusof claim 1, wherein the evacuation cannula is configured to control theremoval of the bone filler material from the expandable membrane duringexpansion to maintain at least one of a desired pressure and a desiredexpansion of the expandable membrane.